This invention relates to an optical electronic arrangement for the color recognition and defect detection of medicinal capsules, and more particularly, relates to an improved arrangement in the electro-optics sub-system of the system disclosed in commonly-assigned U.S. Pat. No. 4,143,770, issued Mar. 13, 1979, the subject matter of which, insofar as it is pertinent to the present invention, is incorporated herein by reference.
The capsule inspection system of the aforementioned patent contemplates an electro-optic sub-system which involves a relatively lengthy alignment procedure. One aspect of this procedure is the necessity of aligning a relatively large number of sensors relative to each other. Alignment time can become costly and increases the efforts needed in maintaining the system. Moreover, any relative alignment errors between sensors tend to degrade the system's sensitivity.
It would thus be desirable to provide an arrangement which reduces the number of alignment steps necessary and which also reduces the relative time variances of signals used in capsule evaluation, and such are principal objects of this invention.
In accordance with the invention, light reflected from a capsule surface is passed through a single lens system onto a multi-aperture mask mounted in front of the common termination of a multichannel fiber optic light guide. Signals from the various channels are passed to individual photodetectors which may be preceded by optical filters. The fibers of the individual channels are arranged in a specified manner relative to the multi-aperture mask at the common termination of the guide. The arrangement is such that the multiple channels may be divided into sets. Channels common to a set transmit essentially equal signals to their respective photodetector filter pairs. The signals in each set are such that they eccentuate certain capsule features. The eccentuated features differ from set to set.
Such an arrangement not only reduces the difficulties in the alignment of optical heads, it enables a reduction in the size of such heads and increases the accuracy of the relative alignment of optical channels. Similar to the concept embodied in the aforementioned reference patent, this invention contemplates four color recognition channels, each being associated with a different portion of the light spectrum, as well as a further channel dedicated to capsule defect detection. However, unlike the concept embodied in the aforementioned reference and patent, this invention contemplates that the four color recognition channels, as well as the defect channel will be derived from a single rather than multiple number of sensors. Preferably three such optical sensor arrangements would be associated to the sensor head, thus providing corresponding selected different views of the inspected object.